This invention relates to the hot rolling of metal slabs to strip thicknesses in coil form having specific weights on the order of 500 pounds per inch of width or greater. In my application Ser. No. 115,611, I disclose a method of modernizing a hot strip mill by eliminating from the finishing train the second finishing stand (F2) and converting the first finishing stand (F1) into a reversing finishing mill stand. This has permitted obsolete or marginally acceptable mills to be converted so as to produce the quality of hot strip product that is in demand in the marketplace today without a large capital expenditure or prohibitive production interrruption. I have found that it is not always practical to convert such obsolete or marginally acceptable mills because of factors such as mill stand spacing, motor room arrangement, facility production commitments and mechanical limitations on the existing finishing stand, F1. However, I have been able to establish that such a final arrangement is so beneficial that it remains advantageous to utilize my rolling techniques through the use of a completely new installation or further refinements of existing installations which have severe limitations which preclude the utilization of the method for modernizing a hot strip mill disclosed in my eariler application.
While hot reversing mills have been utilized heretofore for many years, no one has recognized the tremendous advantages that can be achieved through the appropriate mill arrangement and the method of rolling which I have discovered. Historically, hot mills have been operated at a level to accommodate the tail of the coil which, during processing, becomes the coldest and thus the most difficult to deform. The so-called zoom mills speed up the tail of the coil to limit heat loss. Coil boxes have also been employed. These coil boxes are static in performance and while they reduce the temperature differential from head to tail of the coil, they do it by bringing the hotter end down to the level of the colder end.